This device is basically adapted to various columns test of the existing single and doubleexpansion of hydraulic support. It can achieve inside and outside loading.
试压机基本能适应现有液压支架单、双伸缩的各种规格立柱试验，能实现内、外两种加载方式。
2
The column USES the doubleexpansion and contraction function hydraulic cylinder, increases the power stroke to satisfy the support to adjust the high scope the need.
立柱采用双伸缩作用液压缸，以增加工作行程来满足支架调高范围的需要。
3
The expansion mechanism of hardened cement paste with doubleexpansion sources of entringite and brucite was studied by using theory of fractal geometry and viscoelasticity.